Method of grading roadbeds for concrete roads



R. 0. BAKER.

METHOD OF GRADING ROADBEDS FOR CONCRETE ROADS.

APPLICATION FILED MAY 81 1919. 1,392,674, Patented 001;. 4, 1921.

$015676 i Zaie) WMMM anew? UHTED STATES PA a l ROBERT D. BAKER, OFDETROIT, MICHIGAN.

METHOD OF GRADING ROADBEDS FOR CONCRETE ROADS.

To all whom it may concern:

Be it known that I, ROBERT D. BAKER, a citizen of the United States ofAmerica, residin at Detroit, in the county of Wayne and tate ofMichigan, have invented certain new and useful Improvements in Methodsof Grading Roadbeds for Concrete Roads, of which the following is aspecification, reference being had therein to the accompanying drawings.

The invention relates to the art of constructing concrete roads and itis the object of the invention to facilitate the grading of the road bedso as to secure greater accuracy and to avoid unequal density, tendingto cause cracking of the cement when laid thereon.

In the present state of the art it is usual to perform the grading byroad grading machines in which the blade or scraper is verticallyadjustable and is under the control of an operator. It has been found inpractice that it is practically impossible to accurately follow thegrade in this way, and as a consequence there are places which are toolow and require subsequent filling. Such filled spots are seldom ofexactly the same density as the undisturbed e'arth, so that after thecement is laid une ual settling will often cause it to crack. oreover,the establishment of even an approximate grade by this method requiresskill on the part of the workmen, which increases the cost of theoperation.

With my improved method highly accurate grade is obtained withoutparticular skill on the part of the workmen, while removal of earth frombelow the grade is absolutely prevented. Furthermore, the operation canbe performed more expeditiously and when completed will leave a road bedof uniform density, affording equal. support for the cement laidthereon.

In the drawings:

Figure 1 is a side elevation;

Fig. 2 is a cross-section;

Fig. 3 is a lan view.

The essential features of my improved method is the accurate placing ofa gage extending longitudinally of the road bed and serving to limit thedepth of removal of earth. Preferably such a gage or limiting device isplaced on each side of the road bed and the grading machines areprovided with cooperating means extending across between said gages andlimiting the depth of Specification of Letters Patent.

Patented Oct. 4, 1921.

1919. Serial No. 295,592.

the cutting blade or in other terms, the method consists in establishingmeans along and over the roadway and entirely extraneous thereto, whichcause excavating means used in conjunction therewith to traverse theroadway in planes parallel to a predetermined profile surface and, ifdesired, at such a dlstance below the surface of the ground as wouldinsure substantially equal density of the road bed.

As specifically shown, A are rail sections which are supported on chairsB, such chairs being preferably arranged at the joint between successiverails to form a coupling connection therebetween and also located atintermediate points. The chairs B may be supported upon blocks C, andsuitable vertical adjustment means is provided, such as the pivotal legsD, which may be spread at different angles to raise or lower the rail. Eis a grading machine of any suitable construction, being provided with avertically adjustable cutting blade F mounted on a suitable carriage.The raising and lowering of the blade is controlled by the operatorthrough. suitable means, such as the wheel Q, as is usual with machinesof this type. H is a bar, preferably a tube, which is of sufficientlength to extend across the road bed and over the rails A. This bar isclamped to the vertically adjustable blade F in such a manner that whenthe opposite end portions of the bar come in contact with the rails Afurther downward movement of the blade is prevented. On the other hand,the blade is freely adjustable on its wheeled frame when the bar H isabove the rails.

In carrying out the method, the rails A are first positioned andconnected to each other and to the supporting stand B upon oppositesides of the road bed. The height is then adjusted by raising 0rlowering the chairs in conformity to the level established by thesurveyors stakes, but the upper face of the rail is at a predeterminedheight above the desired rade. The bars H are then clamped to t egraders E in such a manner that the lower or cutting edge of the blade Fwill be exactly on grade when said bars H are resting on the upper facesof the rails. If the road bed is to be rounded, the bars H are of asimilar curve and when working upon opposite sides of the road the barsH are adjusted laterally so as to always maintain the overlap inrelation to the rails A. When the apparatus is adjusted as described,the work of removing the earth may proceed in the ordinary manner andwithout necessity of particular care on the part of the workmen, for itWlll be impossible for the blade to out below the desired depth. -On theother hand, if the ground is high, it may be removed by a series of cutsand the blade may be adjusted in relation to its supporting frame tofacilitate this operation. With horse drawn graders the length of thecutting blade is generally very much less than the total width of theroad bed, which necessitates lateral adjustment of the bars H fordifferent lines of cut. This adjustment may, however, be easilyperformed by providing quick operatin clamps for attaching the bar H tothe b ade, as indicated at J.

- It will be understood that in setting the rails A they need onlyextend for a comparatively short section of the road and after this isbrought to grade said rails may be shifted in position for the gradlngof another section.

What I claim as my invention is 1. The method of grading road beds forconcrete pavement foundations which consists in establishing temporarygaging means along and over the roadway entirely extraneous thereto, thelongitudinal and transverse guiding members of which are substantiallycoincident with the elements of a predetermined profilesurface for the.

roadway, in placing thereon excavatin means, the movements of which arelimited and confined b such guides to planes parallel to the surface insurfacing the ground between the guides therewith.

2. The method of grading road beds for concrete pavement foundationswhich con sists in establishing temporary gaging means along and overthe roadway entirely extraneous thereto, having longitudinal andtransverse guiding members which are adjustable to be brought intosubstantially coincident relation with the elements of a predeterminedprofile surface, in providing excavating means the movements of whichare limited by such gaging means to planes parallel to the profilesurface and in removing the earth along the roadway by such means.

3. The method of grading road beds for concrete pavement foundationswhich consists in establishing gaging means along and over the roadwayand entirely extraneous thereto, having guiding means that areadtsurface for the roadway, in providin justable to be brought intosubstantial coincidence with the longitudinal and transverse elements ofa predetermined profile excavating means for working the roa way, thatare controlled by the gaging means to traverse planes parallel to theprofile surface and at any distance below the latter within the limitsof the apparatus, and in removing the earth along the roadway by saidmeans. a

4. The method of grading road beds for concrete pavement foundationswhich consists in establishing gage rai s along the surface of thesoilin the direction of the right of way at a desired height above theproposed grade and entirely extraneous to the roadway in mountingexcavating mechanism upon the rails to move in planes parallelto apredetermined profile surface at the desired distance below the gagerails and in removing the superfluous dirt by these excavating means.

5. The method of grading road beds for concrete pavementfoundations,.which consists in placing gage rails along the proposedright of way on supports entirely outside the road bed which permitaccurate adjustment of the rails in planes parallel to a predeterminedprofile surface, in placing transverse guiding members upon the railslying parallel to the elements of the predetermined profile surface, inmounting excavating means upon the rails and transverse guides totraverse the surface of the ground in lanes parallel to thepredetermined profi e surface and in removing the superfluous dirt bythese excavatin means.

6. The method of grading road eds for concrete pavement foundations,which consists in mounting sets of gage was on the surface of the groundalong the proposed right of way entirely outside the road bed, providingmeans for vertically adjusting the rails to lie in planes parallel to apredetermined profile surface, in mounting a transverse guiding memberupon the rails to move in a plane parallel to the predeter mined profilesurface, in mounting excavating means upon the guiding rails and guidein such a manner that-it traverses the road bed in planes parallel tothe predetermined profile surface and in excavating the superfluous dirtby these excavating means.

In testimony whereof I aflix my signature.

ROBERT D. BAKER.

